Internal combustion engine



Jan.24, 1939. G.'W.IMERE'DITI-I, 2,145,028

INTERNAL COMBUSTION ENGINE Original FiledAug; 51', 1934 2 Sheets-Sheet 1 Jan. 24, 1939. G, w. MEREDITH 2,145,028.

INTERNAL COMBUST I ON ENGINE Original Filed Aug. 31, 1934' 2 Sheets-Sheet 2 Patented Jan. 24, 1939 UNITED: STATES PATENT OFFICE Application August 31,

1934, Serial No. 742,277

Renewed December 7, 1938 6 Claims.

The two-cycle type of gas engine (the term gas engine being hereinafter employed as synonymous with internal combustion engine), while extremely simple from the standpoint of its mechanism, is ordinarily deficient in performance and in fuel economy when operated at small fractions of its full load capacity. The two-cycle is, furthermore, deficient in smooth operation at low throttle except it be supplied with a mixture overrich in fuel to ensure ignition of the charge. The latter defect is due to the difficulty of providing an ignitable mixture at the igniter because of the preponderance of burned gas remaining from a previous explosion. It is characteristic of the two-cycle gas engine that the compression pressure is approximately the same at low throttle as at full throttle for the reason that the partial vacuum due to throttling will draw gas into the cylinder from the exhaust passages.

The engine hereinafter described and illustrated in the accompanying drawings was invented for the purpose of securing a motor which would not be amenable to the objections above enumerated. Another object of the invention is to provide means whereby a more intimate mixture of the fuel and the air may be secured than is customarily obtained in two-cycle engines in general use. Another object is to secure a certain measure of Stratification between the new charge and the exhaust gases which may remain from aprevious explosion. Another object is to secure, by this Stratification, a certain measure of isolation of the fresh charge surrounding the first point of ignition. A further object of my invention is to provide a unidirectional flow of the exhaust gases and the entering charge thereby to minimize dilution of the latter by exhaust gases.

In processing my invention, I provide a passage adapted to furnish communication between the pre-compression chamber or crank case or other pre-compression chamber. I so arrange and locate this passage that it is open at all times to the power end of the cylinder, and thus comprises a portion of the compression space. I so locate the spark plugs or other ignition means, that one plug is situated close to the port of entrance of the pre-compressed charge into the passage and another in proidmity to the exit from the passage into the cylinder. By locating a spark plug near the entrance to the passage, I ensure the presence of a combustible mixture surrounding the ignition point, and that this mixture shall be free from contamination by spent gas. Although at low throttle there may be a considerable proportion of spent gas in the cylinder, the

entrance of the new mixture will drive this spent gas in advance of the fresh charge and in sufiicient amount that a strata of combustible mixture will remain at entrance of the passage and surround the spark plug at that point. At full 5 throttle or at any reduced throttle such that an ignitable mixture will surround the spark plug proximate to the exit from'the passage into the cylinder, both plugs will function. While the advantage of two firing points in a cylinder is well 10 known in the art, it is appropriate to point out the particular advantage of two ignition points in the engine hereinafter described. In the attenuated compression space provided by the passage the distance to be traversed by the propagated 15 flame from a firing point at one end. of the passage to the other is considerably greater than in a compression space of the usual form. Hence the period of inflammation would be undesirably long were only one plug at the entrance to the '20 passage employed. The use of a second plug near the exit of the passage avoids any difficulty from slow combustion.

The applicant is fully aware that a passage such as described is not new in the art. However, 25 prior designs incorporate means other than the piston for closing the entrance to the passage. Thus there are added complications which detract from the chief feature of the two-cycle type, its mechanical simplicity. The applicant has found '30 that, by a suitable arrangement of the piston, additional means for closing the entrance to the passage need not be employed. For example; when the connecting rod of an engine is at an appreciable angle, the resistance of the load 35 transmits pressure through the rod to thrust the piston against that Wall of the cylinder diametrically opposite to the position of the crank pin during the power stroke. By a suitable arrangement of piston rings, the clearance between the 40 piston and the cylinder may be provided with a seal during that portion of the power stroke in which the pressure dueto the angularity of the connecting rod is insufficient to provide an adequate seal. During the early portion of the compression stroke, when the pressure of the piston due to the angularity of the connecting rod is on that portion of the cylinder wall opposite the entrance to the passage, the pressure against the piston head is comparatively low and the film of 50 lubricating oil provides an adequate seal until the piston rings have passed the entrance to the passage. Therefore, it is not necessary to provide piston rings along the entire length of the piston.

In order to provide turbulence of the mixture 56 iii within the cylinder, and thereby ensure an intimate mixture of the fuel and the air, I so arrange the exit mouth of the passage that the entering charge will be directed at a tangent to the wall of the cylinder. That there may be as complete as possible a stratification of the charge with respect to such spent gases as may remain in the cylinder, I provide that the exit from the passage tothe cylinder be located at the approximate center of the cylinder head, so locating the passage that it will pass over the cylinder and so arrange the mouth of the exit from the passage that the gases therefrom will be directed into the cylinder in an axial direction. In the accompanying drawings I have illustrated the tangential exit and the axial exit separately, the better to describe these two features, both of which may be combined in one design.

In the drawings:

Fig. 1 is an elevation in section of one form of my improved engine, the section being taken along line ll of Fig. 3. In this figure, the piston is at the end ofits inward or compression stroke.

Fig. 2 is an elevation in section of the engine shown in Fig. l, the section being taken along line Il of Fig. 3. In this figure the piston is at the end of its outward or power stroke.

Fig. 3 is a sectional plan of the engine of Figs. 1 and 2, the section being taken through the compression space along line 33 of Fig. 1.

Fig. 4 is a sectional plan of the engine shown in the previous figures, the section being taken along line 4-4 of Fig. 2.

Fig. 5 is a sectional elevation of an alternate form of my improved engine, the section being taken along line 5-5 of Fig. 6.

,Fig. 6 is a sectional plan of the engine of Fig. 5, the section being taken along line 65 of Fig. 5.

Similar numbers refer to similar parts throughout the several views.

The cylinder 1 is shown integral with the crank case 8 of which a fragmentary portion is shown in Figs. 1 and 2. Within the cylinder is the piston 9 provided with the port l0 adapted to provide communication between the lower portion of cylinder 1 and through the cylinder with crankcase 8 with the passage H provided in the wall of cylinder 1, by registration of port 10 with the entrance I2 of the passage II when the piston approaches the end of its power stroke. Passage l I extends along through the Wall of the cylinder, the exit I3 therein provided, communicating with the closed end of cylinder 1. In that wall of the cylinder opposite passage H is provided the exhaust port I4. At a suitable time during the compression stroke, spark plugs l5 and I5 provide ignition means for the combustible mixture within the passage and that between the piston and the closed end of the cylinder.

The piston is linked to crankshaft l6 by means of the connecting rod [1, the lower end of the connecting rod being journalled to crank pin l8 and the upper end of the rod being journalled to piston pin l9.

The piston is provided with three sets of piston rings. The rings 20 function to seal the outer end of the piston, as is customary in all internal combustion engines. The rings 2| seal the piston against leakage past the inner or closed end of the piston, and the rings 22 seal the piston against leakage from passage ll be-- tween the piston and the cylinder to the exhaust port 14 until such time in the power stroke that the angularity of connecting rod [1 will provide suflicient pressure for this purpose. In the figures, the combustible mixture is designated by arrows with full lines, and the products of combustion are designated by arrows with broken lines.

In the operation of my improved engine, the combustible mixture is charged into the crankcase or other pre-compression chamber in any one of the several manners customarily employed therefor. The exact manner of this induction is immaterial to the operation of my improved construction. A charge of mixed air and fuel having been ignited in the compression space, including passage II, the ensuing explosion drives the piston outward, and the exhaust port 14 is uncovered as the piston approaches the end of its power stroke, permitting the spent gas to escape to the atmosphere. Shortly after the exhaust port is opened, the piston port l0 registers with the entrance l2 of passage l l, permitting the pre-compressed charge to flow into passage H, and therethrough into the cylinder. On the outstroke of the piston, the compression stroke, the charge is compressed into the clearance between the end of the piston and the cylinder head and the passage II, the combined volume of the passage and the clearancecomprising the compression space. The mixture is ignited just prior to the completion of the compression stroke, by means of the spark plugs l5 and I5, and the ensuing explosion begins another cycle.

It should be noted that spark plug [5 will be surrounded by combustible mixture after every entry of a fresh charge into passage ll, regardless of how long the engine is throttled. Spark plug I5' will function to shorten the period of inflammation at full or partial throttle.

I claim:

1. In a two-cycle gas engineincluding a cylinder and a crankcase attached to the cylinder, a

piston in the cylinder reciprocable therein, a passage provided ,in the wall of the cylinder, the passage providing communication between the crankcase and that end of the cylinder farthest from the crankcase, a piston-controlled port provided in the wall of the cylinder at the entrance to the passage from the crankcase, the exit of the passage into the cylinder of cylindrical form having the periphery thereof concentric with the axis of the cylinder extended, an igniterin the passage proximate to the entrance thereto, and a second igniter within the cylindrical exit from the passage into the cylinder. I

2. In a two cycle gas engine including a cylinder, and provided with a pre-compression chamber, a piston in the cylinder and reciprocable therein, a passage provided in the wall of the cylinder, the passage providing communication between the cylinder and the pre-compression chamber, a piston-controlled port provided in the wall of the cylinder at the entrance from the precompression chamber to the passage, the exit from the passage into the cylinderof cylindrical form having the periphery thereof concentric with the axis of the cylinder extended, an igniter in the passage proximate to the entrance theretofrom the pre-compression chamber, and a second igniter within the cylindrical exit from the passage into the cylinder.

3. In a-two-cycle gas engine including a cylinder, a passage provided in the wall of the cylinder, a piston in the cylinder and reciprocable therein, the passage providing communication between opposite ends of the cylinder, a pistoncontrolled port provided in the wall of the cylinder at the entrance to the passage, the exit from the passage into the cylinder of cylindrical form having the periphery thereof concentric with the axis of the cylinder extended, an igniter in the passage proximate to the entrance thereto, and a second igniter within the cylindrical exit from the passage into the cylinder.

4. In a two-cycle gas engine including a cylinder and provided with a pre-compression chamber, a piston in the cylinder and reciprocable therein, a passage provided to furnish communication between the cylinder and the pre-compression chamber, the passage continually open to the cylinder, the passage forming with the clearance between the piston and the cylinder at the end of the compression stroke the compression space, a piston-controlled port provided in the wall of the cylinder at the entrance to the passage from the pre-compression space, the exit of the passage into the cylinder being of cylindri cal form, the periphery of said cylindrical exit disposed concentrically about the axis of the cylinder extended, an igniter in the passage proximate to the entrance thereto from the precompression chamber, and a second igniter within the cylindrical exit from the passage into the cylinder.

5. A two-cycle gas engine including a cylinder and a crankcase attached to the cylinder, a piston in the cylinder and reciprocable therein, a passage provided in the longitudinal wall of the cylinder, the passage providing communication between the crankcase and that end of the cylinder opposite the crankcase, a port provided through the cylinder wall at that end of the passage nearest the crankcase, a port provided in the wall of the piston, the piston port adapted to register with the port in the cylinder wall when the piston is approaching the end of its compression stroke, the entire passage being open to the cylinder continuously, an igniter in the passage proximate to said portage in the cylinder Wall, and a second igniter in the passage proximate to the exit therefrom into the cylinder.

6. A two-cycle gas engine including a cylinder and a crankcase attached to the cylinder, a piston in the cylinder and reciprocable therein, a passage provided in the longitudinal wall of the cylinder, the passage providing communication between the crankcase and that end of the cylinder opposite the crankcase, a port provided through the cylinder wall at that end of the passage nearest the crankcase, a port provided in the wall of the piston, the piston port adapted to register with the port in the cylinder wall when the piston is approaching the end of its compression stroke, the exit from the passage into the cylinder being of cylindrical form with the periphery of the exit and concentric with the axis of the cylinder extended, the entire passage open to the cylinder continuously, an igniter in the passage proximate to said port in the cylinder wall, and a second igniter in the exit from the passage into the cylinder.

GEORGE W. MEREDITH. 

